Electronic devices have revolutionized the way human beings work, play, and communicate. In order for electronic devices to communicate, a device that receives the signal must be able to extract information from the received signal. Ideal signal communication channels exist in theory only. In the real world, when signals are transmitted over a communication channel, various types of distortion are introduced into the signal. In order for the receiving device to be able to use the received signal, the receiving device needs to be able to extract the useful information from the received signal despite the distortion.
There are various types of distortion that a signal can experience within a real world communication channel. One type is of course attenuation, where the strength of the channel becomes weaker due to loss in power with unit distance. The most extreme example of this is airwave broadcasts, where power is lost rapidly often at best as a function of the inverse of the square of the distance from transmission. However, even in optical fibers and electrical conductors, signal power attenuates through conversion into heat (i.e., through the creation of phonons). Another type of distortion is jitter in which the phase of the signal at the reception point moves slightly out of synchronization with its original phase of transmission, i.e. a given signal amplitude at the receiver occurs very slightly earlier or later in time than expected, relative to a particular time reference. Echoes may also be generated within the signal due to reflection of the signal. Cross-channel interference or distortion due to external electro-magnetic interference may also introduce noise into the signal.
While an electronic device may be able to extract information from the signal perfectly even with some distortion, the error in the extracted information may increase as the distortion increases. Ultimately, if the distortion is significant enough, no helpful information may be extracted from the received signal. In order to test the ability of the device to receive and extract sufficient information from a distorted signal in order to function properly, channels are constructed that simulate real-world channels. For instance, to emulate 5 kilometers of optical fiber, a roll of 5 miles of optical fiber is set up. However, setting up a channel to produce a signal with distortion is an expensive task.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.